The present invention relates to a thermosetting water-based resin composition, a process for preparing the same, and a molding compound composition comprising the water-based resin composition and a molding product prepared by molding the molding compound composition.
As molding products used in automobile interior materials and construction materials, there have been used various molding products prepared by molding a substrate made of fibers or wood materials with an adhesive such as phenolic resins, urea resins, and melamine resins (Japanese Patent Laid-Open No. Hei 7-1666). In this process, however, there arises a problem of generating formalin from the molding products. In addition, the molding processing is carried out by using a mixture prepared by dissolving an unsaturated polyester resin and an organic peroxide in a polymerizable monomer such as styrene (Japanese Patent Laid-Open No. Hei 10-36653), or by using a mixture prepared by simply mixing an unsaturated polyester resin and an organic peroxide (Japanese Patent Laid-Open No. Sho 52-63286). In these processes, however, there arise such problems that the monomers have odors and that homogeneous curing reaction is less likely to take place.
An object of the present invention is to provide a molding compound composition in which an environmental problem is improved and a homogeneous curing reaction takes place, and a molding product prepared by molding the molding compound composition.
Another object of the present invention is to provide a water-based resin composition suitable for obtaining the molding compound composition, and a process for preparing the same.
These and other objects of the present invention will be apparent from the following description.
The present invention pertains to:
[1] a thermosetting water-based resin composition (hereinafter referred to as xe2x80x9cwater-based resin compositionxe2x80x9d) comprising an oil-soluble initiator of which a temperature for one-minute half-life is from 90xc2x0 to 270xc2x0 C. and a polycondensation resin comprising an unsaturated dicarboxylic acid having a radical-polymerizable unsaturated bond or an acid anhydride thereof as at least one constituent monomer, wherein the polycondensation resin has an acid value of from 3 to 100 mg KOH/g, and wherein said oil-soluble initiator is present in said polycondensation resin;
[2] the water-based resin composition according to item [1] above, further comprising a compound having two or more radical-polymerizable unsaturated bonds;
[3] the water-based resin composition according to item [1] or [2] above, further comprising an acetylene glycol compound represented by the formula (I): 
xe2x80x83wherein each of R1 to R4 is independently a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms; and each of m and n is an integer of 0 or more;
[4] the water-based resin composition according to any one of items [1] to [3] above, further comprising a wax;
[5] a process for preparing a thermosetting water-based resin composition, the process comprising removing an organic solvent by distillation from a raw material composition comprising a polycondensation resin comprising an unsaturated dicarboxylic acid having a radical-polymerizable unsaturated bond or an acid anhydride thereof as at least one constituent monomer, wherein the polycondensation resin has an acid value of from 3 to 100 mg KOH/g; an oil-soluble initiator of which a temperature for one-minute half-life is from 90xc2x0 to 270xc2x0 C.; the organic solvent; a neutralizing agent; and water, to give the thermosetting water-based resin composition comprising the polycondensation resin and the oil-soluble initiator, wherein said oil-soluble initiator is present in said polycondensation resin;
[6] the process according to item [5] above, wherein the raw material composition further comprises a compound having two or more radical-polymerizable unsaturated bonds;
[7] the process according to item [5] or [6], wherein the raw material composition further comprises an acetylene glycol compound represented by the formula (I);
[8] a molding compound composition comprising the water-based resin composition of any one of items [1] to [4] above; and
[9] a molding product prepared by molding the molding compound composition of item [8] above.
One of the large feature of the water-based resin composition of the present invention resides in that an oil-soluble initiator of which a temperature for one-minute half-life of from 90xc2x0 to 270xc2x0 C. is contained in a polycondensation resin particle. When the water-based resin composition comprising the oil-soluble initiator is used for a molding compound composition, the water-based resin composition is adhered evenly on a molding substrate, and when such a molding compound composition is molded (heat-pressed), the oil-soluble initiator is decomposed in the fine particles of the polycondensation resin. Therefore, the homogeneous thermosetting reaction efficiently takes place in an entire molding compound composition, so that there can be exhibited an excellent effect that a molding product having a homogeneous strength is obtained. Incidentally, the water-based resin composition of the present invention does not use at all any material which generates formaldehyde, and the like, and it is also water-based, so that there arise no environmental problems. In addition, in the present specification, the term xe2x80x9coil-soluble initiatorxe2x80x9d refers to an initiator which is dissolved in an organic solvent usable in the preparation process at room temperature (20xc2x0 C.) in an amount of 1% by weight or more. In addition, the term xe2x80x9ctemperature for one-minute half-lifexe2x80x9d refers to a temperature at which the amount of active oxygen in benzene is halved in one minute.
The oil-soluble initiator is not particularly limited, as long as the half-life temperature in one minute is from 90xc2x0 to 270xc2x0 C., preferably from 90xc2x0 to 200xc2x0 C. The oil-soluble initiator includes organic peroxides, azo polymerization initiators, and the like. Among them, the organic peroxides are preferable from the viewpoint of having high reactivity.
The organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyesters, and the like, and those having large amount of active oxygen and small activation energy are preferable. Preferable concrete examples include lauroyl peroxide [temperature for one-minute half-life (referred to the same hereinafter, and omitted): 116.4xc2x0 C.], 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane [147.1xc2x0 C.], 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane [149.0xc2x0 C.], t-butylperoxylaurate [159.4xc2x0 C.], t-butylperoxyisopropylmonocarbonate [158.8xc2x0 C.], t-butylperoxy-2-ethylhexylcarbonate [161.4xc2x0 C.], di-t-butylperoxyhexahydroterephthalate [142.0xc2x0 C.], dicumyl peroxide [175.2xc2x0 C.], 2,5-dimethyl-2,5-di(t-butylperoxy)hexane [179.8xc2x0 C.], di-t-butyl peroxide [185.9xc2x0 C.], t-butylperoxy-2-ethylhexanoate [134.0xc2x0 C.], bis(4-t-butylcyclohexyl)peroxydicarbonate [92.1xc2x0 C.], t-amylperoxy-3,5,5-trimethylhexanoate [130.0xc2x0 C.], 1,1-di(t-amylperoxy)-3,3,5-trimethylcyclohexane [151.0xc2x0 C.], and the like.
The azo polymerization initiator includes 2,2xe2x80x2-azobis-isobutyronitrile [temperature for one-minute half-life (referred to the same hereinafter, and omitted): 116.0xc2x0 C.], 2,2xe2x80x2-azobis-2-methylbutyronitrile [119.0xc2x0 C.], 2,2xe2x80x2-azobis-2,4-dimethylvaleronitrile [104.0xc2x0 C.], 1,1xe2x80x2-azobis-1-cyclohexanecarbonitrile [141.0xc2x0 C.], dimethyl-2,2xe2x80x2-azobisisobutyrate [119.0xc2x0 C.], 1,1xe2x80x2-azobis-(1-acetoxy-1-phenylethane) [111.0xc2x0 C.], and the like.
These oil-soluble initiators may be alone or in admixture of two or more kinds.
The content of the oil-soluble initiator is preferably from 0.1 to 30 parts by weight, more preferably from 0.1 to 20 parts by weight, still more preferably from 0.5 to 20 parts by weight, most preferably from 0.5 to 10 parts by weight, based on 100 parts by weight of the polycondensation resin, from the viewpoints of the curing rate required for the material to be molded and a balance between the strength of the molding compound and the storage stability of the water-based resin composition.
The polycondensation resin usable in the present invention may be any kind as long as the polycondensation resin comprises an unsaturated dicarboxylic acid having a radical-polymerizable unsaturated bond or an acid anhydride thereof as at least one of constituent monomers, wherein the polycondensation resin has an acid value of from 3 to 100 mg KOH/g. Concretely, polyesters and polyester-polyamides are preferable, from the viewpoints of easiness in the preparation of the water-based resin composition, which is a water-based dispersion, adhesion to various substrates, and no use of formalin as the raw material.
The polyester usable in the present invention can be prepared, for instance, by polycondensing an acid component with a polyol component.
The unsaturated dicarboxylic acid having a radical-polymerizable unsaturated bond, or an acid anhydride thereof used as an acid component includes maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, and acid anhydrides thereof, and maleic acid, fumaric acid, maleic anhydride, and tetrahydrophthalic anhydride are preferable. The content of the unsaturated dicarboxylic acid or acid anhydride thereof is preferably from 20 to 100% by mol, more preferably from 50 to 100% by mol of the acid component.
The other acid component usable in the present invention is not particularly limited, and for instance, the following polycarboxylic acids or derivatives thereof can be used.
The polycarboxylic acids or derivatives thereof are not particularly limited, and non-radically reactive, dicarboxylic or tricarboxylic acids having 4 to 40 carbon atoms are preferably used. Examples thereof include dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, succinic acid, a dimer acid, alkenylsuccinic acids (C4 to C20), cyclohexanedicarboxylic acid, and naphthalenedicarboxylic acid; tricarboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid); acid anhydrides thereof; and lower alkyl esters (C1 to C4) thereof.
The polyol component is not particularly limited. Preferable are aliphatic polyols having 2 to 10 carbon atoms such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, glycerol, pentaerythritol, trimethylolpropane, sorbitol, and 1,6-hexanediol; aromatic polyols such as bisphenol A, hydrogenated bisphenol A; and alkylene (C2 to C3) oxide adducts (the additional molar number of alkylene oxide being from 2 to 10) prepared therefrom. Especially, propylene oxide adduct of bisphenol A is preferable from the viewpoint of heat resistance.
The polycondensation of the polyol component and the acid component may be carried out by a known process, comprising, for instance, polycondensing a polyol component with an acid component at a temperature of 180xc2x0 to 250xc2x0 C. in an inert gas atmosphere, and its terminal point may be determined by monitoring a softening point (Tm), an acid value (AV), or the like, which can be used as a reference for a molecular weight of the resulting product.
The molar ratio of the polyol component to the acid component may be appropriately determined from the values of the AV, the number-average molecular weight, the glass transition point (Tg), or the like of the polyester, and it is preferable that the molar ratio (polyol component: acid component) is from 1:0.6 to 1:1.5.
In addition, during the polycondensation, there can be appropriately used additives including esterification catalysts such as dibutyltin oxide and polymerization inhibitors such as hydroquinone monomethyl ether.
The polyester-polyamide usable in the present invention can be prepared by a well-known method, for example, by polycondensation by adding an amine derivative to ingredients comprising the acid component and the polyol component used in the preparation of the polyester. The amine derivative is not particularly limited, and includes polyamines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, and xylylenediamine; aminocarboxylic acids such as methylglycine, trimethylglycine, 6-aminocaproic acid, xcex4-aminocaprylic acid, and xcex5-caprolactam; and amino alcohols such as propanolamine. From the viewpoint of the solubility to an organic solvent, methylglycine, trimethylglycine and 6-aminocaproic acid are preferable.
The molar ratio between the polyol component, the acid component and the amine derivative in the polyester-polyamide may be appropriately determined from the values of the AV, the number-average molecular weight, the Tg, or the like of the polyester-polyamide, in the same manner as those of the polyester.
The AV determined by the method in accordance with JIS K 0070 of the polycondensation resin obtained by the above process is from 3 to 100 mg KOH/g, preferably from 10 to 70 mg KOH/g. The AV is 3 mg KOH/g or more, from the viewpoint of obtaining a stable water dispersion, and the AV is 100 mg KOH/g or less, from the viewpoint of making the polycondensation resin water-insoluble, thereby having excellent compatibility with the oil-soluble initiator. Incidentally, the AV may be adjusted by regulating the molar ratio of the acid component/polyol component of the raw material, the reaction time, and the like.
In addition, it is desired that a saponification value (SV) determined by the method in accordance with JIS K 0070 of the polycondensation resin is from 150 to 750 mg KOH/g, preferably from 250 to 600 mg KOH/g, more preferably from 250 to 300 mg KOH/g. The SV is preferably 150 mg KOH/g or more, from the viewpoint of increasing the strength after curing, and the SV is preferably 750 mg KOH/g or less, from the viewpoints of having an appropriate affinity with water and obtaining a molding material having excellent water resistance. Incidentally, the SV may be adjusted by regulating the molecular weights of the acid component and the polyol component, the ratios thereof, and the like.
Further, the hydroxyl value (OHV) determined by the method in accordance with JIS K 0070 of the polycondensation resin is preferably from 1 to 50 mg KOH/g. Moreover, it is preferable that the Tg of the polycondensation resin (determined by differential scanning calorimeter) is from 0xc2x0 to 100xc2x0 C., that the Tm (determined by flow tester method) is from 800 to 180xc2x0 C., and that the number-average molecular weight (value converted as polystyrene by GPC method) is from 1000 to 50000. Also, when the polycondensation resin is a polyester-polyamide, it is desired that the amine value of the polycondensation resin determined by the method in accordance with ASTM D2073 is 10 mg KOH/g or less.
In addition, it is necessary that carboxyl group of the polycondensation resin is at least partly neutralized, and for instance, the polycondensation resin is a neutralized product by adding a neutralizing agent to a solution comprising the polycondensation resin.
The neutralizing agent is not particularly limited, as long as it is capable of ionizing the carboxyl group. The neutralizing agent is preferably hydroxides of alkali metals, alkaline earth metals, and the like, and various amines, and especially hydroxides of alkali metals are preferable. The amount of the neutralizing agent used is preferably 0.8 to 1.4 equivalent in proportion to the carboxyl group of the polycondensation resin. Incidentally, the neutralizing agent may be used by itself, or it may be diluted or dissolved in a very small amount of water.
Although the content of the polycondensation resin in the water-based resin composition may differ depending upon the mold processing methods, the content is preferably from 5 to 60% by weight, more preferably from 15 to 50% by weight, from the viewpoint of attaining an excellent balance between the strength required and the stability of the dispersion. Especially, when a compound having two or more radically-polymerizable unsaturated bonds is used as described below, the content of the polycondensation resin is more preferably from 15 to 60% by weight, still more preferably from 25 to 60% by weight.
The water-based resin composition of the present invention may further comprise a compound having two or more radically-polymerizable unsaturated bonds (hereinafter referred to as xe2x80x9cunsaturated bonds-containing compoundxe2x80x9d).
Since the water-based resin composition comprises the unsaturated bonds-containing compound, the cross-linking density of the polycondensation resin after curing becomes high, so the strength is enhanced, so that there is exhibited an effect that a water-based resin composition having excellent heat resistance and water resistance can be obtained. Further, when the water-based resin composition comprising the unsaturated bonds-containing compound and the oil-soluble initiator is used as a molding compound composition, resin fine particles can be homogeneously immersed, applied, mixed or adhered to a molding substrate. Therefore, when the molding compound composition is molded (heat-pressed), radicals are generated from the oil-soluble initiator in the fine particles of the polycondensation resin, so that the polymerization reaction takes place between unsaturated bonds of the polycondensation resin and the unsaturated bonds-containing compound. Thus, there is exhibited an excellent effect that a homogeneous curing reaction efficiently takes place in the entire molding compound composition, thereby making it possible to obtain a molding product having a homogeneous strength.
The unsaturated bonds-containing compound usable in the present invention include one or more compounds selected from the group consisting of compounds having (meth)acryl groups at both ends, compounds having allyl group, and compounds having divinyl group. Among them, when the molding compound composition prepared from a water-based resin composition is heat-cured, the compounds having allyl group are preferable from the viewpoints of having functions of being compatible with the polycondensation resin and thereby lowering the melting point of the polycondensation resin in a heated state prior to curing; the improvement in strength of the molding product after curing owing to high reactivity caused by lowering of the melting point of the polycondensation resin and also to an increase in the cross-linking density caused by an increase in the amount of the unsaturated bonds; the storage stability of the water-based resin composition; and the odor during molding. Concretely, diallyl compounds such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl maleate, diallyl itaconate, diallyl hexahydrophthalate, diailyl phthalate prepolymer, and diallyl isophthalate prepolymer; and triallyl compounds such as triallyl 1,2,4-benzenetricarboxylate are more preferable.
In addition, compounds having (meth)acryl groups at both ends include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylates, neopentyl glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate and the like, and triethylene glycol dimethacrylate, polyethylene glycol dimethacrylates and the like are preferable. The preferable compounds having divinyl group include divinylbenzene, divinylnaphthalene, and the like.
These unsaturated bonds-containing compounds may be used alone or in admixture of two or more kinds.
The content of the unsaturated bonds-containing compound is preferably from 5 to 80 parts by weight, more preferably from 10 to 60 parts by weight, based on 100 parts by weight of the polycondensation resin, from the viewpoint of making the strength of the resulting molding product high, and improving the heat resistance and the water resistance.
The water-based resin composition of the present invention may further comprise an acetylene glycol compound represented by the formula (I): 
wherein each of R1 to R4 is independently a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms; and each of m and n is an integer of 0 or more.
During the preparation of the water-based resin composition, especially when an organic solvent is removed by distillation from a raw material composition comprising the raw materials of the resin composition, since the formation of the resin fine particles in the phase inversion process accompanied by removal of the organic solvent by distillation, and its dispersion stability can be improved and curing reaction caused by the elevation of viscosity of the dispersion and the accumulated heat can be prevented by using the acetylene glycol compound represented by the formula (I), the water-based resin composition which has a high solid content and low viscosity can be efficiently obtained. Therefore, since the resulting water-based resin composition has excellent handleability, a high solid content and a low water content, there is exhibited an excellent effect that the molding time can be shortened.
In the acetylene glycol compound represented by the formula (I), each of R1 and R4 more preferably has 2 to 4 carbon atoms, and each of R2 and R3 more preferably has 1 to 2 carbon atoms.
Examples of the acetylene glycol compound represented by the formula (I) include compounds represented by the formula (a) to (c): 
wherein m and n are as defined above. Among them, the compounds represented by the formula (c) are preferable, and those having a total of m and n of from 3 to 40 are more preferable, and those from 8 to 35 are still more preferable.
The content of the acetylene glycol compound represented by the formula (I) is preferably from 0.5 to 30 parts by weight, more preferably from 1 to 25 parts by weight, still more preferably from 2 to 20 parts by weight, based on 100 parts by weight of the polycondensation resin, from the viewpoint of the formation and dispersion stability of the resin fine particles, and the suppression of the curing reaction caused by the elevation of viscosity of the dispersion and accumulated heat, and further the homogeneous mixing and adhesion of the resin fine particles and the substrate.
In addition, it is preferable that the water-based resin composition of the present invention further comprises a wax, from the viewpoints of improvement in releasability of the molding product from a molding machine during molding, and improvement in water resistance of the molding product. The wax includes paraffin waxes, microcrystalline waxes, petrolatum, carnauba waxes, and emulsions containing them.
The content of the wax in the water-based resin composition is preferably from 0.05 to 10% by weight, more preferably from 0.1 to 5% by weight, from the viewpoints of the releasability of the molding product from a molding machine during molding, and the water resistance of the molding product.
Next, the process for preparing a water-based resin composition of the present invention will be explained. The water-based resin composition of the present invention is prepared by a so-called xe2x80x9cphase-inversion emulsification.xe2x80x9d An example of such a preparation process comprises removing an organic solvent by distillation from a raw material composition comprising the polycondensation resin, the oil-soluble initiator, the organic solvent, the neutralizing agent and water, and optionally at least one of the unsaturated bonds-containing compound, the acetylene glycol compound represented by the formula (I) and the wax. Concretely, it is preferable that a process comprises dissolving the polycondensation resin and the oil-soluble initiator, and optionally the monomers having unsaturated bonds and the unsaturated bonds-containing compound in an organic solvent; further adding a neutralizing agent and water, and optionally an acetylene glycol compound represented by the formula (I), a wax and a surfactant; and thereafter removing the organic solvent by distillation from the mixture to carry out the phase inversion to an aqueous system. The phase inversion may take place when water is added, and it is more preferable that the phase inversion takes places during the removal of the organic solvent by distillation, from the viewpoint of obtaining a stable dispersion.
In the present invention, by employing the above process, there can be exhibited excellent effects that there can be readily obtained a water-based resin composition in which the polycondensation resin particles in fine particle form having an average particle size of preferably 5 xcexcm or less, more preferably 2 xcexcm or less, still more preferably 1 xcexcm or less are dispersed in an aqueous medium, wherein the oil-soluble initiator and optionally the unsaturated bonds-containing compounds are contained in the polycondensation resin.
Incidentally, the organic solvent usable in the present invention is preferably ketone solvents having 3 to 8 carbon atoms, such as acetone, methyl ethyl ketone and diethyl ketone; ether solvents having 4 to 8 carbon atoms such as tetrahydrofuran (THF), and the like, and acetone, methyl ethyl ketone and THF are more preferable. It is preferable that the amount of the organic solvent is from 100 to 600 parts by weight, based on 100 parts by weight of the polycondensation resin.
In addition, the amount of water used is preferably from 100 to 1000 parts by weight, based on 100 parts by weight of the polycondensation resin. In this case, when various surfactants such as anionic and nonionic surfactants, especially sulfates of higher alcohols, sulfates of polyoxyethylene alkyl ethers, dialkylsulfosuccinates, formalin condensates of xcex2-naphthalenesulfonates, are further added to water in an amount of 1 to 20 parts by weight, based on 100 parts by weight of the polycondensation resin, the average particle size of the resulting fine particles can be made advantageously small, and the resin concentration can be desirably increased.
In addition, a water-soluble persulfate such as sodium persulfate, potassium persulfate or ammonium persulfate, or a water-soluble azo compound such as 2,2-azobis (2-amidinopropane) dihydrochloride, 4,4xe2x80x2-azobis(4-cyanovaleric acid) or 2,2-azobisisobutylamide dehydrate is preferably added as a water-soluble initiator, because radicals are also formed from the above compounds by heating during molding, whereby the curing reaction is further accelerated. The water-soluble initiator may be added during mixing of the substrate and the water-based resin composition.
In addition, the removal of the organic solvent by distillation is preferably carried out, for instance, under reduced pressure at 30xc2x0 to 70xc2x0 C. It is desired that the content of the organic solvent is adjusted to preferably 1% by weight or less, more preferably 0.1% by weight or less. Moreover, it is more preferable that a pH of the resulting treated solution is adjusted to a range of from 6 to 10. The pH adjustment can be made by using the above neutralizing agent.
The fine particles of the water-based resin composition prepared by the above process have an average particle size of preferably from 0.5 to 5000 nm, more preferably from 1 to 2000 nm, still more preferably from 1 to 1000 nm, in order to homogeneously cure the molding product. Here, the average particle size is appropriately adjusted by changing, for instance, the molecular weight, the AV, the degree of neutralization, the conditions for phase-inversion emulsification, or the like of the polycondensation resin.
The liquid viscosity of the water-based resin composition is preferably from 5 to 1000 mPaxc2x7s, more preferably from 10 to 800 mPaxc2x7s, still more preferably from 20 to 600 mPaxc2x7s, from the viewpoints of the handleability, the suppression of the curing reaction caused by accumulated heat of the liquid, and the homogeneous mixing and adhesion of the resin fine particles and the substrate. The liquid viscosity can be determined on the basis of the rotating oscillation-type viscometer.
In order to adjust the liquid viscosity of the water-based resin composition within the above range, it is preferable to add the acetylene glycol compound and the various surfactants listed below during the preparation of the water-based resin composition, or to the prepared water-based resin composition. When the entire solid content concentration of the water-based resin composition is 30% by weight or more, this process is especially effective and preferable.
The water-based resin composition of the present invention may further comprise, in addition to the above ingredients, various conventionally known additives, including, for instance, ultraviolet ray absorbents such as benzotriazole and benzophenone, mildew-proof agents such as chloromethylphenol, chelating agents such as EDTA, oxygen absorbents such as sulfites, and the like.
It is preferable that the water-based resin composition is self-dispersible. Alternatively, the resin composition may be formed by adding a surfactant and dispersing the mixture with a forced agitation dispersion device such as a homomixer, filmics, or an emulsifier such as an attritor.
The water-based resin composition of the present invention is excellent not only in its thermosetting properties, but also in the storage stability, heat resistance and water resistance, so that the water-based resin composition is useful for a raw material for a molding product. The molding compound composition can be obtained by applying, immersing, spray-coating, foam-coating, or the like the water-based resin composition of the present invention to a substrate.
The substrate is not particularly limited, and there can be used inorganic fibers and synthetic fibers such as glass fibers and carbon fibers; organic fibers such as natural fibers; pulp powder; wood powders, wooden chips, and the like.
In addition, there may be used as occasion demands a catalyst, a curing agent, a curing aid which is solid at ambient temperature and has low level of odor such as an oligomer and prepolymer having unsaturated bonds, a cross-linking accelerator, a releasing agent such as an amide wax, a synthetic wax, a synthetic latex or a metal salt of a fatty acid, a filler such as talc, silica, calcium carbonate, clay or aluminum hydroxide, known additives, packing agents and extenders. These optional additives may be added during mixing of the substrate with the water-based resin composition.
The content of the substrate in the molding compound composition is preferably from 1 to 99.5% by weight, more preferably from 20 to 98% by weight, from the viewpoints of the specific gravity of the molding product and the strength of the molding product.
The content of the water-based resin composition in the molding compound composition is preferably from 0.5 to 99% by weight, more preferably from 2 to 80% by weight, from the viewpoints of the specific gravity of the molding product and the strength of the molding product.
A process for molding the molding compound composition of the present invention having the above constitution is not particularly limited, and a known process, such as pressure-molding with heating, compression-molding, laminating-molding, injection-molding, or extrusion-molding, can be employed. In addition, the molding compound composition may be molded after preheating it. In addition, after molding the molding compound composition once, the molding may be carried out again (secondary molding).
Since the molding product obtained by the above process does not cause environmental problem and has sufficient strength, it can be suitably used for automobile interior materials, construction materials, and the like.